Sorry for that. We have constant DDoS today. Although we have anti DDoS server option paid, there is still a problem. Stratum is working fine. Blocks are being found and payouts are made. We are working with OVH on solving the problem.
What the fuck are you doing?
Put it behind Cloudflare, it's free.
With SSL it's $20 / month.
www.cloudflare.com(Obvious after setting up CF, ask OVH for new IP, as your current IP is known to DDOSer.)